This invention relates generally to an apparatus for the air treating of articles, such as comestibles carried on a spiral conveyor, and more particularly to such an apparatus having centrally located, axially spaced air deflecting baffles for confining the flow of air directly through successive turns of an endless, foraminous conveyor belt when the articles supported thereon have such a predetermined small size as to permit the free flow of air directly through the belt. Otherwise, the baffles deflect the flow of air in lateral directions across the articles carried on successive turns of the belt from a central opening formed by the belt, into reentrant chambers of a cylindrical housing in which the conveyor belt is mounted, and laterally back to the central opening in a zig-zag path over the articles supported on the belt when the article size is greater than the aforementioned small size so as to impede flow of air directly through the successive turns of the belt.
Typically, in an apparatus for cooling or freezing articles supported on a spiral conveyor, the conveyor is confined within the airflow path such that the supported articles to be cooled or frozen may impede the free flow of air through the successive turns of the belt from one side thereof to the other during conveyor movement. All the products may therefore become unevenly or incompletely cooled or frozen, which is undesirable, which affects the quality of articles frozen or cooled as well as the efficiency of the cooling system.